ROME (AP) — Verdicts are expected Monday in the trial of hundreds of people accused of membership in Italy’s ’ndrangheta organized crime syndicate, one of the world’s most powerful, extensive and wealthy drug-trafficking groups.

The trial started almost three years ago in the southern Calabria region, where the mob organization was originally based. The ’ndrangheta quietly amassed power in Italy and abroad as the Sicilian Mafia lost influence.

The syndicate now holds almost a monopoly on cocaine importation in Europe, according to anti-mafia prosecutors who led the investigation in southern Italy. The organization also has bases in North and South America and is active in Africa, Italian prosecutors maintain, and ’ndrangheta figures have been arrested in recent years around Europe and in Brazil and Lebanon.

The trial took place in a specially constructed high-security bunker. Part of an industrial park in Lamezia Terme, the bunker is so vast that video screens were anchored to the ceiling so participants could view the proceedings.

More than 320 defendants are charged with crimes that include drug and arms trafficking, extortion and mafia association, a term in Italy’s penal code for members of organized crime groups. Others are charged with acting in complicity with the ’ndrangheta without actually being a member.

The charges grew out of an investigation of 12 clans linked to a convicted ‘ndrangheta boss. The central figure, Luigi Mancuso, served 19 years in Italian prison for his role in leading what investigators allege is one of the ‘ndrangheta’s most powerful crime families, based in the town of Vibo Valentia.

Based almost entirely on blood ties, the ‘ndrangheta was substantially immune to turncoats for decades, but the ranks of those turning state’s evidence are becoming more substantial. In the current trial, they include a relative of Mancuso’s.

Several dozen informants in the case came from the ‘ndrangheta, while others formerly belonged to Sicily’s Cosa Nostra.

Despite the large number of defendants, the trial wasn’t Italy’s biggest one involving alleged mobsters.

In 1986, 475 alleged members of the Sicilian Mafia went on trial in a similarly constructed bunker in Palermo. The proceedings resulted in more than 300 convictions and 19 life sentences. That trial helped reveal many of the brutal methods and murderous strategies of the island’s top mob bosses, including sensational killings that bloodied the Palermo area during years of power struggles.

In contrast, the trial involving the ‘ndrangheta was aimed at securing convictions and sentences based on alleged acts of collusion among mobsters and local politicians, public officials, businessmen and members of secret lodges to show how deeply rooted the syndicate is in Calabria.

“The relevance (of this trial) is enormous,” Italian lawmaker former anti-mafia chief prosecutor and lawmaker Federico Cafiero De Raho, a former chief anti-mafia prosecutor, told The Associated Press in an interview. “First of all, because every trial against the ‘ndrangheta gives a very significant message to the territory, which is not only the Calabrian one, but the national territory.”

“But it has repercussions also at a European and world level, because the ‘ndrangheta is one of the strongest organizations in the world, able to manage the international traffic of narcotics, as well as many other activities,” Cafiero De Raho added.

Awash in cocaine trafficking revenues, the ’ndrangheta has gobbled up hotels, restaurants, pharmacies, car dealerships and other businesses throughout Italy, especially in Rome and the country’s affluent north, criminal investigations have revealed.

The buying spree spread across Europe as the syndicate sought to launder illicit revenues but also to make “clean” money by running legitimate businesses, including in the tourism and hospitality sectors, investigators alleged.

“Arrests allow their activities to be halted for a time, but the investigations determine the need for further investigations each time,” Cafiero De Raho said.